Japanese Patent Laid-Open Publication No. 1982-124438 discloses a mixed gas of CF4 and O2 used as an etching gas to etch SiC with a plasma treatment. Japanese Patent Laid-Open Publication No. 1987-216335 discloses another mixed gas of CHF3 and O2 used as etching gas to etch SiC with a plasma treatment.
However, these etching gases have a lower SiC etching rate, a lower etching selectivity of SiC with respect to SiO2 (SiC etching rate over SiO2 etching rate), and a lower etching selectivity of SiC with respect to an organic mask (SiC etching rate over an etching rate of the organic mask).